from ..core.problem_definition_base import ProblemDefinitionBase
from ..core.simulation_parameters import SimulationParameters
from typing import Dict, Any, Optional, List

# FEniCSx相关的导入，同样使用条件导入
try:
    import dolfinx
    from dolfinx import fem, mesh
    import ufl
    from ufl.core.expr import Expr as UFLExpr # 显式导入并重命名以避免冲突
    from mpi4py import MPI
    FENICSX_AVAILABLE = True
except ImportError:
    FENICSX_AVAILABLE = False
    # 用于类型提示的虚拟类型
    class fem:
        class Function: pass
        class DirichletBC: pass
    class mesh:
        class MeshTags: pass
    class ufl:
        class Form: pass
        class Argument: pass
        class Measure: pass
        # class Expr: pass # 为 ufl.core.expr.Expr 添加虚拟类型
    class UFLExpr: pass # 虚拟类型 UFLExpr
    class MPI:
        class Comm: pass

class ElectrochemistryProblemMembrane(ProblemDefinitionBase):
    """
    求解膜/离聚物相电势 (phi_m) 的问题定义。
    这通常控制质子在质子交换膜 (PEM) 和催化剂层内的离聚物中的传输。
    """
    def __init__(self,
                 problem_name: str, # 例如, "phi_m_pem", "phi_m_cathode_cl"
                 fem_entities: Dict[str, Any],
                 material_functions: Dict[str, Any],
                 params: SimulationParameters,
                 # 可选的 UFL 表达式，用于从其他物理场耦合的项
                 volumetric_current_source_term_ufl: Optional[UFLExpr] = None, # J_m (A/m^3)
                 domain_tags: Optional[mesh.MeshTags] = None,
                 dx_measure: Optional[ufl.Measure] = None,
                 ds_measure: Optional[ufl.Measure] = None,
                 boundary_markers: Optional[Dict[str, Any]] = None,
                 comm: Optional[MPI.Comm] = None,
                 **kwargs):
        """
        初始化膜/离聚物相电化学问题。

        参数:
            problem_name (str): 此膜相电化学问题的唯一名称。
            fem_entities (Dict[str, Any]): 基本的 FEniCSx 实体。
            material_functions (Dict[str, Any]): 材料属性，期望包含有效的膜/离聚物电导率 ('membrane_conductivity' 或 'ionomer_conductivity')。
            params (SimulationParameters): 所有模拟参数。
            volumetric_current_source_term_ufl (Optional[UFLExpr]): 
                体积电流源项的 UFL 表达式 (例如，来自催化剂层中的电化学反应)。
            domain_tags (Optional[dolfinx.mesh.MeshTags]): 域的网格标签。
            dx_measure (Optional[ufl.Measure]): 用于体积积分的 UFL 度量。
            ds_measure (Optional[ufl.Measure]): 用于面积积分的 UFL 度量。
            boundary_markers (Optional[Dict[str, Any]]): 将边界名称映射到标记 ID。
            comm (Optional[MPI.Comm]): MPI 通信器。
            **kwargs: 额外的关键字参数。
        """
        self.volumetric_current_source_term_ufl = volumetric_current_source_term_ufl
        # fem_entities 中的变量键，例如 "phi_m" 或 problem_name
        self.variable_key_in_fem_entities = kwargs.pop('variable_key', 'phi_m')

        super().__init__(problem_name=problem_name,
                         fem_entities=fem_entities,
                         material_functions=material_functions,
                         params=params,
                         domain_tags=domain_tags,
                         dx_measure=dx_measure,
                         ds_measure=ds_measure,
                         boundary_markers=boundary_markers,
                         comm=comm,
                         **kwargs)

    def setup_problem(self) -> None:
        """
        为膜/离聚物相电势设置变分问题。
        控制方程 (电荷守恒，Ohm 定律的稳定形式):
            ∇ ⋅ (-κ_m_eff ⋅ ∇φ_m) = S_φ_m
        其中 S_φ_m 是体积电流源项 (例如，来自电化学反应)。

        变分形式 (假设 κ_m_eff 不是 φ_m 的函数，对于线性形式):
            ∫_Ω (κ_m_eff ⋅ ∇trial_φ_m ⋅ ∇test_φ_m) dΩ = ∫_Ω S_φ_m ⋅ test_φ_m dΩ + BC_terms
        """
        if not FENICSX_AVAILABLE:
            print(f"警告: FEniCSx 不可用。跳过 {self.problem_name} 的 setup_problem()。")
            self._bilinear_form = None
            self._linear_form = None
            self._bcs = []
            return

        # 1. 识别要求解的 fem.Function (例如, phi_m) 及其函数空间
        solution_vars = self.fem_entities.get('solution_variables', {})
        if self.variable_key_in_fem_entities in solution_vars:
            self._variable_to_solve = solution_vars[self.variable_key_in_fem_entities]
            if not isinstance(self._variable_to_solve, fem.Function):
                raise TypeError(f"'{self.variable_key_in_fem_entities}' 必须是 dolfinx.fem.Function 类型。")
            V_phi_m = self._variable_to_solve.function_space
            if V_phi_m is None: raise ValueError(f"'{self.variable_key_in_fem_entities}' 的函数空间为 None。")
        else:
            function_spaces = self.fem_entities.get('function_spaces', {})
            if self.variable_key_in_fem_entities in function_spaces:
                V_phi_m = function_spaces[self.variable_key_in_fem_entities]
                raise KeyError(f"'{self.variable_key_in_fem_entities}' 在 solution_variables 中未找到，虽然在 function_spaces 中找到了。请确保 solution_variable 已创建。")
            else:
                raise KeyError(f"求解变量 '{self.variable_key_in_fem_entities}' (用于膜相电势) 或其函数空间未找到。"
                               f"可用的 solution_variables: {list(solution_vars.keys())}。 "
                               f"可用的 function_spaces: {list(function_spaces.keys())}。")

        # 2. 识别试函数和试验函数
        self._test_function = ufl.TestFunction(V_phi_m)
        self._trial_function = ufl.TrialFunction(V_phi_m)

        trial_phi_m = self._trial_function
        test_phi_m = self._test_function

        # 3. 获取材料属性
        # 尝试通用的 'membrane_conductivity'，然后是更具体的 'ionomer_conductivity'
        kappa_m_eff = self.material_functions.get("membrane_conductivity")
        if kappa_m_eff is None:
            kappa_m_eff = self.material_functions.get("ionomer_conductivity")
        if kappa_m_eff is None:
            raise ValueError("材料属性 'membrane_conductivity' 或 'ionomer_conductivity' 未找到。")
        if not hasattr(kappa_m_eff, '__mul__'): # 检查是否与 UFL 兼容
             raise TypeError("材料 'membrane_conductivity'/'ionomer_conductivity' 与 UFL 不兼容。")

        # 4. 定义变分形式分量
        dx = self.dx_measure
        if dx is None: raise ValueError(f"'{self.problem_name}' 未提供 dx_measure。")

        self._bilinear_form = kappa_m_eff * ufl.dot(ufl.grad(trial_phi_m), ufl.grad(test_phi_m)) * dx
        self._linear_form = ufl.as_ufl(0) * test_phi_m * dx # 初始化

        if self.volumetric_current_source_term_ufl is not None:
            if not hasattr(self.volumetric_current_source_term_ufl, '__mul__'):
                raise TypeError(f"{self.problem_name} 的 volumetric_current_source_term_ufl 与 UFL 不兼容。")
            self._linear_form += self.volumetric_current_source_term_ufl * test_phi_m * dx

        # 5. 定义狄利克雷边界条件
        self._bcs = []
        # 示例: 通常，一个参考电势被设置，例如在阳极 GDL/CL 界面处 phi_m = 0
        # anode_ref_marker = self.boundary_markers.get("anode_cl_gdl_interface") 
        # if anode_ref_marker is not None:
        #     # ref_potential_dofs = fem.locate_dofs_topological(V_phi_m, V_phi_m.mesh.topology.dim - 1, anode_ref_marker)
        #     # self._bcs.append(fem.dirichletbc(fem.Constant(V_phi_m.mesh, PETSc.ScalarType(0.0)), ref_potential_dofs, V_phi_m))

        # print(f"信息: 问题 '{self.problem_name}' (ElectrochemistryProblemMembrane) 设置完成。") 